Back in October 2015, the results from the SPLIT trial1 confirmed that the use of a balanced crystalloid solution as a resuscitation fluid in critically ill patients did not reduce the risk of developing acute renal failure compared to the use of a saline solution (SS). Contradicting important prior studies,2 those conclusions complicated a fundamental debate.

Two years later, October 2017, the results from the SMART trial were published: “Balanced crystalloids versus saline in the intensive care unit: study protocol for a cluster-randomized, multiple-crossover trial”.3

The SMART trial is a cluster-randomized, multiple-crossover trial that was conducted between July 1, 2015 and April 30, 2017 in 5 American ICUs of one single university hospital. Patients over 18, who had been admitted to 5 selected ICUs (medical, surgical, neurological, trauma, and cardiac), and who had been prescribed one IV crystalloid solution were included in the study. Same as the SPLIT trial, the SMART trial compared to use of a SS to a balanced crystalloid solution. The primary goal of the study was to determine the MAKE composite score (Major Adverse Kidney Events: intra-hospital death, renal replacement therapy, or renal dysfunction) within the first 30 days after the ICU admission (MAKE-30).4

The results presented, with 15,802 patients recruited, show that the outcome of MAKE-30 was present in 14.3% of patients from the group who received balanced SS compared to 15.4% of the patients from the second group (p=0.04), with a 0.91 adjusted odds ratio in favor of the balanced fluids (95% CI: 0.82–0.99). In this case, the difference between the arms was triggered by the hospital mortality rate (11.1 versus 10.3%; p=0.06).5

These findings, that are consistent with the different mortality rate seen in patients from the SPLIT trial (7.6 versus 8.6% in favor of the balanced solution), cannot be considered a casual finding.1,5

With the data presented from the SMART trial, the number of patients needed to treat (NNT) to save just one life would be 94. And even though this figure may be underestimated, it is really important to think about the impact that such a routine daily measure as picking up this or that resuscitation fluid can have on the costs and human lives here at our ICUs.

Also, balanced crystalloid solutions are more expensive. However, if we could use these fluids to avoid the occurrence of major adverse renal events, we would definitely find it cost-effective to use them, even if it wasn’t a short-term cost-effectiveness.